This is what we tell our readers in every PSU review we publish: "HardOCP’s testing methodology is intended to very much push power supplies to advertised wattage ratings in temperatures that will represent some of the hottest computer enthusiast cases. So if a unit passes all our testing it is definitely not something to take lightly. In fact we expect more power supplies to fail our testing than make it through unscathed."

Our testing at 45C ambient temperature (our full testing procedure is outlined here) is the issue with our Corsair RM testing that caused it to fail our internal testing. As we state, that is HOT. We designed our tests this way on purpose. We wanted to put the PSUs we test into a very stressful environment when we test. This way when we make a recommendation on what PSU you should buy, we can make that suggestion and be very comfortable with it. That said, it is highly unlikely that any enthusiast "in the know" would ever see temperatures so high in their custom build even if they only take a few minutes to address proper airflow inside their computer case.

Corsair let us know it was taking measures to address our testing criteria. Here is what it had to say:

The RM Series PSUs, like all Corsair PSUs, are designed and tested using methodologies that closely simulate the environment of an enthusiast/gaming PC under heavy, sustained workloads. Our testing has proven that the cooling system of the RM Series will engage and provide the necessary cooling during heavy real world use.

That said, we’re enthusiasts, too. We understand why Kyle and Paul came to the conclusions they did, and based on their feedback, we’ve implemented a design change that will allow our RM Series PSUs to go the extra mile and endure the extreme synthetic test conditions of the HardOCP test lab.

We have changed the value of the resistor between the thermistor and the fan controller so the fan turns on much sooner than the temperature that would trigger OTP. Therefore the fan should always turn on before OTP is triggered; preventing the PSU from shutting down before it is necessary.

This change has been implemented in all RM PSUs produced since mid October. While we honestly believe even extreme users will never run into the issue encountered during HardOCP’s synthetic test, those end users that want to know if their RM can endure HardOCP’s torture test can identify the updated PSUs by a lot code of 1341 or higher.

Given these changes, we would fully expect the Corsair RM series PSU that we tested to meet our internal testing standards and would earn at the very least a "HardOCP PASS" grade.